Aillih w l@larch 20, 1967 Dr. Dear Dr. Attached is a proposii fbz'a Research Contract, Physiological ,Mechanisms Underlying the. Electrodermal,Response and their Behavioral, Significance 'wftich will 2allow continuation and extension of,work performed under ou \roriginal Contra.ct The designated principal'Lnvestigator would again be Dr. - I It is 'requested t]@at this contract, if approved, become efl'ective june'l, 1967. S%erely yours, Approved for Release 2 @3 -Ii maul @l Prop _qsa Piiysiological \4echanisms Underlylng the Electrodermal Response and their Behavicral Significance From March 207, 1967 Period of Work This proposal woule cover one year of effort. Facilities '-@-@a t@iori-td'equipm'ent originally available, there isno-'w--'an additional 4-cha D.C. polygraph purchased under the current contract, and a 2-channel magnetic .tape recorder with FM compoients for recording of biolcgi2cal signals. Amount of Support An estimate of costs is attached. Contract-lat firtancial ar-rangements are proposed as exist under the current contract with the exception that indirect costs be calculated at the negotiated rate of 30 percent. Ref)orts @@pose@d-t a@schedullng-of pro.gress rep4orts-be'c6ntinued on the. same. -Contrdet Principal Invest Cost Estimate FrLncipal investigator (part-time) Research Assistant (full-time) Electronics Techniciaii (half-time) Subjects Stenographic Services Reproduction Services Expendable Supplies (Paper, chemicals, electron ic components, etc.) Solid state special purpose comput9er components Impedance Bridge Magnetic -Recording Tape Travel @(2:coordinati@@@ Sub-To@al Overliead at 307( (LNegotiaced Ea'-e) Tol.al PHYSIOLOGICAL NIECI[ANISNIS UNDERLYING THE ELECTRODERP@LNL RESPONSE AND THEIR BEHAVIORAL SIGINIFICANCF, 1. INT.RODUCTION Reference is maje to the description of kic@g-@gtnq and statement of proposed work described under current contract r i rTtnT @ Ed in June 1966. FL:rtlier reference is madtto an interim 'Progress Report dated February 15, 1967, which describes progress to January 31, 1967. The original contract was aimed at a systematic investigation of the basic physiological mechanisms responsible for electrodermal reflex events in the hopes that the understanding of their nature would aid i)2ehavioral iriterpretation and afford a rational basis for effective data treatment. Attention was to be given to the relative involvement (or lack of involvement) of vasomotor, sudom6tor and epidermal activi ty in this reflex, to the special characteristics of the response which might be associated with each component, to the, prin--iples governing the addition of 2component activities '* and to the specific classes of stimuli which evoke activity in the respective components. Efforts were @_,o be made to identify the nature of the biological adaptaton signified by the activity of each component in efforts to recognize their psychological significance. The initial phases of this work (as described in the February.15, 1967, interim progre2ss report) consisted of experiments as follows: (a) Comparison of microelectrode recordings from sweat pores and areas between sweat pores. These have since been extended to comparison of surface recordings with those at the deepest level of the stratum corneum. (b) Comparison of recordings from the corneum in different states of hydration. (c) Recording2s from cat foot-pad under'varying patterns of s-@-imulatioa of the sympathetic nerve supply. (d) Recordings of potential responses from the r,,al.1 :)late which is allegedly free of sweat glands. (e) Study of the effect of surface electrolytes on the specific components of the skin potential response. (f) Production of local ele8ctrodertnal responses by mechanical stimulation (calibrated stretch) and alteration of this response by cliemi-cal agents, ischemia, temperature change, and combl-iation with activity of central origin. -2- ExarnLriation of the effects on skin potential response of vascular changes produced by engorgement (venous cuff), arterial occlusion, or exsanguination by a directed massage. (h) Comparison of electroder-mal behavior as measured by constant voltage vs constz.-it current systems. 2 The results of these experiments together with those alreadv reported in the literature were utilized in the development of a new hypothesis describing the peripheral proce@ses involved in the elect-roderrnal response. 'Ibis model, described in the interim report, ascribes conductance changes having a slow recovery rate and negative potential waves, also of slow recovery rate, to the 2 rise of sweat in the ducts. 'rbe fast recovering conductance wavi@s and the positive potential waves are attributed to behavior of a neurally controlled membrane readuv accessible to surface solution, and involved in the rapid reabsorption of water fron-t the skin surface. An analysis of the manner in which these comp:)nents combine was used to explain the co -nplex wave forms o2btained under actual recordng conditions. From this model it wa7s concluded that the half-time of the recovery process of the skin conductance response should be a meaningful index of the arrm)unt of fast- recovering (membrane) component in the response. A seric-s of behavioral experiments was analyzed with the use of this index to determ@ ine whether it distinguished d2ifferent behavioral states, for example, alerdng for a task as opposed to execution of the task, and relaxing as opposed to task performance. The measure successfully-di,5tingLilshed between these conditio@s even cascs to do so. 11. PROPOSED INVESTIGATIONS A. Contiriuation of Physiological Investiga2tion Although considerable progress has beert made in clarifying the nature of peripheral mechanisms, several important questions remain to be resolved. These will receiv-3 continued investigation in terms of experiments described in the current contract. Among these are: 1. Does the nail bed in fact represent a sweat-gland free area and, if so, may vascular 2processes explain the nail potential responses of central origin and the lo(@al positive potential responses obtained by mechanical displacement? This will be investigated by simultaneous recordings of skin potentials and reflectance plethysmographic changes from the nail plate. Efforts will also be made to alter the potential responses with electrolytes applied to the nail plate, to test for a surfac9e membrane effect. 2. Do local potential responses (prcduced mechanically) depend upon z, surface membrane alone, or may a vascular component be involved? TI)c effect of surface ;igciits ajid cxsaiiguinatio--i experiments point to a surface membrane as the responsible cle2r-nent but surface reflectance monitoring undertaken since the last interim report de.-noiistratesa marked similarity between the form of the local potential responce and that of the change of surface optical opackty followiiig the nieci-,anical stimulus even in the exsang,uinated -extremity. The attack- on i-iiis problem will consist of attempts to selectively extinguish either the local potential response (e.g., with surface tariaestlieties) or the vasomotor accompaniment, e.g., by using et(-,ctrical or vibratory stiniuli to produce the local response. 3. Is the activity of the sweat gland observable at the surface 2 only as a secondary effect of ttie rise of sweat in the ducts, or are there electrical changes at the s.ecretory membrane which cortribute to the surface potential respolise? nd his co-work-ers have shown that Lntra-ductat electrodes in t-@e cat sw and do not indicate responses when they are. inserted deeper than the level of the germinating laye2r. Ftecent experiments under the present contract indicate that the human sweat gland behaves differently in t--iat responses may be recorded at deeper levels. It remains to be decided whether these are due to pickup from nearby structures or in fact originate in the sweat gland. 4. In addition to the three critical questions stated above, 2 numerous lines of approach to the clarification of mechanisms, described in the original proposal, reml ain to be undertaken. Special attention will be givea to the combination of high frequency impedance measurement with potential and D.C. resistanep, measurement,, and to the effects of pre-exposure to various cu--reat densities upon the positive and negative waves and2 upon sweat gland and epidermal responses, B. Development of the Recovery Half-Time Index because of the high success with which the t/2 recovery index distinguishes qualitatively different behavioral states, a keye:fort in the continuing program will be directed toward rendering this mezisure maximally effective. T'@-is investigation shall b2e concerned wi : 1. The development of a method for automatic on-line presentation of the recovery limb index. 2. The determination as to whether some fraction of the recovery time other than 5070, e.g., one third recovery to base line, is a more sensitive measure. Various fractions of the recovery time are rea&-ty selected by the automati3c circuitry now planned for this operation. Alik . -4- 3. The determination of the extent of the amplitude range in which this measure maintains its independence of amplitude. 4. The relationship of changes in the recovery index to various peripheral phy2siological processes as deterrniried by independent measures su-ch as vapor production, A.C. vs D.C. impedance, etc. 5. The classes of stimuli which tend to pro&-ce shortening or lengthening of the recovery index. 6. The I ability of this measure during short term alteration of stimulus conditions. 2 C. Application of Electrodermal Measures as Indices of Bio-Psychologit;al Adaptability The @nterpretation of electrodermal activity as a biologically useful - adaptation implies that its occurrence La response to a,-t arousing situation may indicate effective behavior. There are, however, two -additional requirements which must be evidenced 2by the behavioz sample before this conclusion can be reached, na-.nely that the type of adaptation be approprlate to the demands of the situation both qualitatively and quantitatively. The first implie% for example, that a defensive response to a situation which appropriately calls for maximum information intake is ineffective behavior. ne second implies that autonomic ac2tivation should be graded in proportion to the situational demand$ and most important, that the activation shctuld rapidly diminish as soon as the demands of the situation are reduced. In other words the effective individua , in the irlterests of biologica'L economy.,would not remain continuously a::tivated, but should be able to shift rapidly to the resting state while maintaining a system of sentrins for defense purposes. He should then be canable, upon being alerted by his sentries (i.e., his r-2ceptive screen) to shift gears rapidly to the activated state. The dissection c,-f the electrodermal response iitto qualitatively dilferent adaptive reflexes syould allow evaluation of the qualitative appropriateness of the elici2ted activation. The recovery index should allow observation of shifts in arousal even when the amplitude of the background activity, fails to differentiate functional states. The appraisal of an individual's adaptability to environmental demands will be determined by exposing him to a sequence of rest conditions'.alternated at unannounced times with tasks or s2tresses of varying e-emands (qualitatively and quantitatively)* An index of adaptability will bq cortst.-ucted from the rapidity of activation and (especially) relaxation and the degree to which it is qualitatively appropriate to the task in terms of three categories of behavioro defense,, aggressive task orientation, or information intake. This adaptability index will be validated a7gainst personal histories Cob or military), clinical judgement of behavior, and performance on a battery of tasks aimed at assessing this ability. AMhk 'T ATTAC!i'.%lE:N -B to "vas selected 4 I for this follow-on action because'of,the excellert @er Dr. nve forn-La@nce of the prin,cipa during the initial con4@ract period.